XRENDERING-446: Provide original cause of error in Macro error message even...

XRENDERING-446: Provide original cause of error in Macro error message even when there's no nested exception
* Fix tests

xwiki-platform-core/xwiki-platform-rendering/xwiki-platform-rendering-macros/xwiki-platform-rendering-macro-useravatar/src/test/resources/macrouseravatar3.test

@@ -10,7 +10,7 @@
 beginDocument
 beginMacroMarkerStandalone [useravatar] [username=XWiki.UserNotExisting]
 beginGroup [[class]=[xwikirenderingerror]]
-onWord [Failed to execute the [useravatar] macro. Click on this message for details.]
+onWord [Failed to execute the [useravatar] macro. Cause: [User [XWiki.UserNotExisting] is not registered in this wiki]. Click on this message for details.]
 endGroup [[class]=[xwikirenderingerror]]
 beginGroup [[class]=[xwikirenderingerrordescription hidden]]
 onVerbatim [org.xwiki.rendering.macro.MacroExecutionException: User [XWiki.UserNotExisting] is not registered in this wiki${{{regex:.*}}}] [false]